The present invention relates to a novel salt form of the active compound pantoprazole. The novel salt form can be employed in the pharmaceutical industry for the preparation of medicaments.
Prior art
Pyridin-2-ylmethylsulfinyl-1H-benzimidazoles, such as are disclosed, for example, in EP-A-005129, EP-A-0166287, EP-A-0174726 and EP-A-0268956, have, on account of their H+/K+ATPase-inhibiting action, considerable importance in the therapy of diseases which are due to increased gastric acid secretion. Examples of commercially available active compounds from this group are 5-methoxy-2-[(4-methoxy-3,5-dimethyl-2-pyridinyl)methylsulfinyl]-1H-benzimidazole (INN: omeprazole), 5-difluoromethoxy-2-[(3,4-dimethoxy-2-pyridinyl)methylsulfinyl]-1H-benzimidazole (INN: pantoprazole), 2-[3-methyl 4-(2,2,2-trifluoroethoxy)-2-pyridinyl)methylsulfinyil]-1H-benzimidazole (INN: lansoprazole) and 2-{[4-(3-methoxypropoxy)-3-methylpyridin-2-yl]methylsulfinyl}-1H-benzimidazole (INN: rabeprazole).
A common property of the abovementioned pyridin-2-ylmethylsulfinyl-1H-benzimidazoles is the acid sensitivity-which is in the end indispensable for their efficacy-of these active compounds, which is seen in their strong tendency to decompose in a neutral and, in particular, acidic environment, strongly colored decomposition products being formed.
In the past, there have been considerable efforts, despite the acid sensitivity of the pyridin-2-ylmethylsulfinyl-1H-benzimidazoles, to obtain stable and storable oral administration forms which contain these pyridin-2-ylmethylsulfinyl-1H-benzimidazoles. Such stable and storable oral administration forms (e.g. tablets or capsules) are now obtainable. The preparation of these oral administration forms, however, is comparatively complicated and also certain precautions must be taken with respect to the packaging, in order that the administration forms have an adequate storage stability even under extreme storage conditions (e.g. in the tropics at high temperature and high atmospheric humidity).
The International Patent Application WO97/41114 describes a specific process for the preparation of magnesium salts of pyridin-2-ylmethylsulfinyl-1H-benzimidazoles. Inter alia, the preparation of the magnesium salt of pantoprazole is also described by way of example. According to the analysis data indicated, the salt prepared is pantoprazole magnesium in anhydrous form.